The present invention relates to instruments and methods used in connection with preparation of tissue of a patient, particularly the tissue of the heart of a mammalian subject. In a particular instance, the instruments and methods of the present invention are used in preparing the heart for implantation of a ventricular assist device.
In certain disease states, the heart lacks sufficient pumping capacity to meet the needs of the body. This inadequacy can be alleviated by providing a mechanical pump referred to herein as a heart pump or a ventricular assist device (“VAD”) to supplement the pumping action of the heart.
The VAD is typically connected to the heart by an inflow tube, most commonly to the left ventricle. Typically, one end of an outflow tube is connected to the VAD and the other end is connected to the aorta. Once connected, the VAD and the heart both pump blood from the left ventricle to the ascending or descending aorta to improve blood flow. Alternatively, a VAD may be connected to the ventricle to assist the heart in pumping blood into pulmonary arteries. In some instances, the VAD is connected to the heart through the use of a sewing ring, as disclosed in U.S. Published Patent Application Nos. 2004/0171905 and 2007/0134993, the disclosures of which are both hereby incorporated by reference herein as if fully set forth herein. An example of the sewing ring is illustrated in FIG. 3A. A separate surgical tool is then used to cut or core a hole in the ventricle centered within the sewing ring. The VAD is typically attached to the sewing ring at the site of the cored hole in the ventricle. Alternatively, the VAD can be secured to the sewing ring such that the VAD is positioned through the heart wall and thus a portion of the VAD is within the heart and a portion is outside the heart.
As used currently, the step of coring the tissue within the sewing ring can be difficult to perform. Typically, the surgeon must advance the coring tool and then retract it. This requires two separate and opposite motions. Moreover, if the coring tool is movably mounted in a housing so that the surgeon can aim the coring tool by aiming the housing, the surgeon must advance the coring tool relative to the housing and then retract the coring tool relative to the housing, all while attempting to maintain the housing in position relative to the patient.
Thus, there is a need for an improved coring tool that is simple to actuate and perform the tissue coring, and further allows the operator to maintain affirmative pressure against the heart wall and/or sewing ring during such actuation.